Field of the Invention
The present invention relates to a setting device for a minute hand of a timepiece, in particular of a chronograph, with a central arbor which bears a seconds hand and which has a plurality of receiving regions, with a gearwheel which is fixedly connected on the central arbor for driving about the latter in a first receiving region, with a heart-shaped reset to zero mechanism which is fixedly fastened on the central arbor for driving about the latter in a second receiving region, with a release snail cam which is arranged on the central arbor for driving about the latter in a third receiving region and which has a radially encircling control cam which rises in a ramp-like manner and along which a trip-dog of a minute control lever, which is pivotable about a pivot axis, slides under resilient prestress during the rotational movement of the release snail cam and, after a sliding distance corresponding to sixty seconds and overcoming the point of the largest radius, drops onto the point of the smallest radius of the release snail cam, with a minute control pawl which is arranged on the minute control lever and by means of which, when the trip-dog of the minute control lever drops onto the point of the smallest radius of the control cam, a minute counter wheel which is mounted rotatably can be advanced by a minute step, wherein the release point of the advancement can be set in an adjustable manner by the minute control lever.
Description of Related Art
A setting device for a minute hand of a timepiece is known from EP 1 953 612.
In the case of timepieces, at the moment of the zero passage of the seconds hand, both the trip-dog of the minute control lever is intended to drop onto the point of the smallest radius of the release snail cam and the minute counter wheel is intended to advance via the control lever and the control pawl by a step. Due to tolerances during the production and assembly, the simultaneouseous of said two functions cannot easily be achieved. In EP 1 953 612, an adjustment possibility with the aid of an eccentric is provided for this purpose, in which an opening which receives the head of the eccentric is provided in the minute counter wheel. A finger of the eccentric then engages in the release snail cam and, by rotation of the eccentric head, permits a variation in the setting of the angle of the release snail cam with respect to the gearwheel. The angular point at which the trip-dog of the setting lever drops from the point of the largest radius onto that of the smallest radius can thereby be set.
A disadvantage of the solution according to this prior art document is that, for the use of the eccentric, the gearwheel has to be realized in a corresponding material thickness. A certain moment of inertia is associated therewith because of the radial extension of the gear wheel and the radially remote material provided as a result.
Another earlier solution to this problem is known from DE 198 52 347, in which the trip-dog of the minute control lever itself can be set in the circumferential direction of the control cam. For this purpose, an eccentric with which the position of the point of the trip-dog can be set is provided on the minute control lever itself.